Sodium-sulfur battery, and a battery system using same

A sodium-sulfur battery comprising:

• a cell container for a negative electrode containing sodium;
• a cell container for a positive electrode containing a positive mold composed of sulfur or sodium polysulfide;
• a sodium ion conductive solid electrolyte separating said negative electrode and said positive electrode;
• an insulator fixed to said cell container for the negative electrode and said cell container for the positive electrode, the insulator being connected to said solid electrolyte, wherein said cell container for the positive electrode is an integrated assembly consisting of a plurality of members, composed of high corrosion resistant materials of Co base or Ni base alloys containing Cr, and joined by welding;
• and
• a readily deformable portion is provided for said cell container for the positive electrode,
• wherein said material for composing said cell container for the positive electrode is one of:
• (i) a Co base alloy consisting of at least 30 wt. % Co, 18.about.32 wt. % Cr, and at the utmost 0.2 wt. % C, and
• (ii) a Ni base alloy consisting of at least 40 wt. % Ni, 18.about.32 wt. % Cr and at the utmost 0.2 wt. % C.

A sodium-sulfur battery comprising:

• a cell container for a negative electrode containing sodium;
• a cell container for a positive electrode containing a positive mold composed of sulfur or sodium polysulfide;
• a sodium ion conductive solid electrolyte separating said negative electrode and said positive electrode;
• an insulator fixed to said cell container for the negative electrode and said cell container for the positive electrode, the insulator being connected to said solid electrolyte, wherein said cell container for the positive electrode is an integrated assembly consisting of a plurality of members, composed of an alloy material containing Fe as a main component, 22.about.32 wt. % Cr, 14.about.24 wt. % Ni, utmost 0.2 wt. % C, and joined by welding;
• and
• means to reduce a stress added to a welded portion of said integrated assembly by said positive mold.

A sodium-sulfur battery comprising:

• a cell container for a negative electrode containing sodium;
• a cell container for a positive electrode containing a positive mold composed of sulfur or sodium polysulfide;
• a sodium ion conductive solid electrolyte separating said negative electrode and said positive electrode;
• an insulator fixed to said cell container for the negative electrode and said cell container for the positive electrode, the insulator being connected to said solid electrolyte, wherein said cell container for the positive electrode is an integrated assembly consisting of a plurality of members, composed of an alloy material containing Fe as a main component, 22.about.32 wt. % Cr, 14.about.24 wt. % Ni, utmost 0.2 wt. % C, and joined by welding;
• and
• a readily deformable portion is provided for said cell container for the positive electrode.

A sodium-sulfur battery comprising:

• a cell container for a negative electrode containing sodium;
• a cell container for a positive electrode containing a positive mold composed of sulfur or sodium polysulfide;
• a sodium ion conductive solid electrolyte separating said negative electrode and said positive electrode;
• an insulator fixed to said cell container for the negative electrode and said cell container for the positive electrode, the insulator being connected to said solid electrolyte, wherein said cell container for the positive electrode is an integrated assembly consisting of a plurality of members, composed of high corrosion resistant materials of Co base or Ni base alloys containing Cr, and joined by welding;
• and
• means to reduce a stress added to a welded portion of said integrated assembly by said positive mold, wherein said means to reduce a stress includes a member extending away from a wall of the cell container for the positive electrode and interposed between a weld of said integrated assembly and the insulator.

A sodium-sulfur battery comprising:

• a cell container for a negative electrode containing sodium;
• a cell container for a positive electrode containing a positive mold composed of sulfur or sodium polysulfide;
• a sodium ion conductive solid electrolyte separating said negative electrode and said positive electrode;
• an insulator fixed to said cell container for the negative electrode and said cell container for the positive electrode, the insulator being connected to said solid electrolyte, wherein said cell container for the positive electrode is an integrated assembly consisting of a plurality of members, composed of high corrosion resistant materials of Co base or Ni base alloys containing Cr, and joined by welding;
• and
• a readily deformable portion is provided for said cell container for the positive electrode, wherein said readily deformable portion is a bellows, provided for the cell container for the positive electrode.

A sodium-sulfur battery comprising:

• a cell container for a negative electrode containing sodium;
• a cell container for a positive electrode containing a positive mold composed of sulfur or sodium polysulfide;
• a sodium ion conductive solid electrolyte separating said negative electrode and said positive electrode;
• an insulator fixed to said cell container for the negative electrode and said cell container for the positive electrode, the insulator being connected to said solid electrolyte, wherein said cell container for the positive electrode is an integrated assembly consisting of a plurality of members, composed of an alloy material containing Fe as a main component, 22.about.32 wt. % Cr, utmost 0.2 wt. % C, and joined by welding;
• and
• means to reduce a stress added to a welded portion of said integrated assembly by said positive mold, wherein said means to reduce a stress includes a member extending away from a wall of the cell container for the positive electrode and interposed between a weld of said integrated assembly and the insulator.

A sodium-sulfur battery comprising:

• a cell container for a negative electrode containing sodium;
• a cell container for a positive electrode containing a positive mold composed of sulfur or sodium polysulfide;
• a sodium ion conductive solid electrolyte separating said negative electrode and said positive electrode;
• an insulator fixed to said cell container for the negative electrode and said cell container for the positive electrode, the insulator being connected to said solid electrolyte, wherein said cell container for the positive electrode is an integrated assembly consisting of a plurality of members, composed of an alloy material containing Fe as a main component, 22.about.32 wt. % Cr, utmost 0.2 wt. % C, and joined by welding;
• and
• a readily deformable portion is provided for said cell container for the positive electrode, wherein said readily deformable portion is a bellows, provided for the cell container for the positive electrode.